9000 Hatchback L4-2290cc 2.3L DOHC Turbo EFI (1994)
Braking Sensor/Switch: Description and Operation
The travel sensor is mounted on the vacuum servo and consists of a set of resistors connected in series which are read by a sliding contact.
This enables the travel sensor to detect a total of seven pedal position points for evaluation by the Electronic Control Unit (ECU).
A pump test begins every time the car exceeds 30 km/h after starting. The pump then runs for around 300 m/sec..
If the pedal has reached the seventh position of the travel sensor (see table below), the pump will be started regardless of whether braking requires
Antilock Brake System (ABS) or not. If the ECU does not modulate the pedal to the preceding position, the ABS warning light will come on.
If the ECU then detects a defect in the power supply, the ABS will be completely inoperative. Since vacuum servo manufacturing tolerances may vary,
the vacuum servo is marked with a colour code. Adjusting sleeves of different colors (depending on size) are supplied with the vacuum servo and travel
sensor as spare parts. On replacement of the vacuum m servo or travel sensor, the sleeve with the same colour as the colour code on the vacuum servo
must be fitted on the tip of the travel sensor (1).
